A black matrix on a color filter substrate and/or an array substrate plays an important role in a thin film transistor liquid crystal display (TFT-LCD). The black matrix can improve the contrast of the liquid crystal display and prevent the colors of different sub-pixels from mixing with each other. It can also be used to block and absorb incident light so as to avoid light on the active layer of the thin film transistor, thereby ensuring the excellent off-state characteristics of the thin film transistor. Besides, the black matrix can block the gap between the signal line and the pixel electrode on the array substrate to prevent light leakage and to avoid reduction of the image contrast.
Metal chromium is typically used to prepare a black matrix. However, metal chromium leads to serious environmental pollution, and the resources for metal chromium are quite limited. A black photoresist material can also be obtained by refining carbon black with a super-dispersant to replace metallic chromium as a material for preparing a black matrix. However, in order to meet the requirement for better display performance of the filter, there is an increasing need to develop a new black photoresist material and to optimize the formation thereof so as to form a black photoresist material with a narrow particle size distribution range, a small particle size and good stability.